Monitoring of Prefailure Phase and Detection of Tool Breakage in Micro-Drilling Operations

The purpose of this study is to investigate effectiveness of the thrust force, the motor current of spindle, and the AE signals from workpiece for the monitoring of the prefailure phase and the detection of the tool breakage in drilling holes through a thin stainless steel plate (JIS SUS304). The thrust forces, the motor current, and the AE signals were measured in micro-drilling tests by using the micro-drills of 0.1 - 0.3 mm in diameter. After some considerations of experimental data, it was revealed that the thrust force is the most suitable for both the monitoring of the prefailure phase and the detection of the tool breakage, the motor current for the monitoring of the prefailure phase of the tool breakage, and the AE signal for the detection of the tool breakage.